title: Plasma cotinine indicates an increased risk of preeclampsia in previous and passive smokers.
abstract: OBJECTIVE
  Self-reported tobacco smoking in pregnancy has been consistently associated with a decreased risk of developing preeclampsia, but the evidence has been limited and inconsistent for previous and passive smokers. Misclassifications and inaccuracies of self-reported tobacco exposure may disguise the true relationship. This study aimed to assess the association of gestational hypertension and preeclampsia with maternal smoking status as ascertained by plasma cotinine.
  
  
  METHODS
  This was a prospective study of 605 pregnant women without chronic hypertension. Maternal smoking status at 24-26 weeks' gestation was defined by plasma cotinine: >3.0 ng/mL "current smokers," 0.20-3.00 ng/mL "previous and passive smokers," and <0.20 ng/mL "nonsmokers."
  
  
  RESULTS
  Compared to nonsmokers, the risk of developing preeclampsia did not change significantly for current smokers, but increased significantly (adjusted odds ratio, 6.06; 95% confidence interval, 2.32-15.85; P < .001) for previous and passive smokers. There were no significant differences in the risk of developing gestational hypertension only.
  
  
  CONCLUSIONS
  Previous and passive smoking may increase the risk of preeclampsia. Avoidance of exposure to environmental tobacco smoke in pregnancy may decrease the risk of preeclampsia.
authors.affiliation: Department of Obstetrics and Gynecology, Sainte-Justine Hospital, University of Montreal, Montreal, Quebec, Canada; Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.
authors.forename: Zhong-Cheng
authors.initials: ZC
authors.lastname: Luo
authors.affiliation: Department of Endocrinology and Nephrology, Quebec Hospital Research Center, Laval University, Quebec City, Quebec, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Julien
authors.affiliation: Department of Obstetrics and Gynecology, Sainte-Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Shu-Qin
authors.initials: SQ
authors.lastname: Wei
authors.affiliation: Department of Obstetrics and Gynecology, Sainte-Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Francois
authors.initials: F
authors.lastname: Audibert
authors.affiliation: Department of Obstetrics and Gynecology, Kingston General Hospital, Queen's University, Kingston, Ontario, Canada.
authors.forename: Graeme N
authors.initials: GN
authors.lastname: Smith
authors.affiliation: Department of Obstetrics and Gynecology, Sainte-Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
mesh_terms: D000328:Adult; D003367:Cotinine / Q000097:blood*; D005260:Female; D006801:Humans; D018811:Maternal Exposure / Q000009:adverse effects*; D011225:Pre-Eclampsia / Q000097:blood / Q000209:etiology*; D011247:Pregnancy; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000097:blood; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution; D003367:Cotinine
keywords: cotinine; gestational hypertension; passive smoker; preeclampsia; previous smoker